In my application I need to sample a number of bipolar signals coming from piezo sensors, and detect their relative time difference (for multilateration based on difference time of arrival).
I expect the signals themselves have a fairly low bandwidth, around 10kHz, but I'd like to determine (among others) when their zero-crossings happen with an accuracy of 1-2μs.
I'm considering the ADS8661 as the ADC: its sampling rate of 1.2MSPS seems accurate enough, and the presence of a built-in analog frontend would make my schematic simpler.
I see that the frontend has a low-pass filter with a cutoff frequency of 15kHz. Given that it will remove all higher frequencies, is there a risk that it will make zero-crossing detection less precise?